EVP_MD4(3ossl)

💖 EVP_MD4(3ossl) — the OpenSSL manual, bestie edition 💖

okay so real talk, this is the OpenSSL manpage for EVP_md4, and I'm gonna walk you through it like we're texting at 2am. it's giving crypto history, it's giving legacy provider drama, it's giving "please don't call this in a loop". let's go ✨

---

🌸 NAME 🌸

EVP_md4 — MD4 For EVP. that's it, that's the whole vibe. MD4, but make it EVP. 💅

---

🎀 SYNOPSIS 🎀

#include <openssl/evp.h>

const EVP_MD *EVP_md4(void);

literally just one function, no cap. she takes no arguments and hands you back a pointer. iconic behaviour. 🫶

---

🦋 DESCRIPTION 🦋

so. MD4. she's a cryptographic hash function, standardized in RFC 1320, designed by Ronald Rivest, and first published all the way back in 1990. she's a legend, she's an OG, she walked so the rest could run. 💜

⚠️ but here's the tea: this implementation is only available with the legacy provider. not the default one. the legacy one. so if you're out here wondering why EVP_md4() is giving you nothing, that's why. go check your provider situation. 🔥

✨ EVP_md4() ✨

the MD4 algorithm which produces a 128-bit output from a given input. one hundred and twenty-eight bits, periodt. 🎀

---

💀 NOTES 💀

okay bestie, listen up, because this is the part where I need you to pay attention. 🙈

developers should be aware of the negative performance implications of calling this function multiple times. like, not me calling EVP_md4() in a hot loop and wondering why everything is slow 😭

instead, you should consider using EVP_MD_fetch(3) with EVP_MD-MD4(7) instead. that's the move. that's the slay. ✨

see "Performance" in crypto(7) for further information. iykyk. 💅

---

👑 RETURN VALUES 👑

these functions return a EVP_MD structure that contains the implementation of the message digest. so like, a whole little struct of digest goodness, handed to you. 🎁

see EVP_MD_meth_new(3) for details of the EVP_MD structure — that's where the lore lives. 🌈

---

⭐ CONFORMING TO ⭐

IETF RFC 1320. she conforms, she's certified, she's official. no cap. ✅

---

🌈 SEE ALSO 🌈

• evp(7)
• provider(7)
• EVP_DigestInit(3)

go read those too, bestie, they're part of the extended universe. 🦋

---

💖 COPYRIGHT 💖

Copyright 2017-2023 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.

---

and that's the whole page, bestie!! this was OpenSSL version 3.5.9, dated 2026-09-29, and honestly? she ate. go hash responsibly, and remember: legacy provider, EVP_MD_fetch(3), no hot loops. mwah 💅💖✨